The Shelby GT350 Mustangs were powered by a 302 cubic-inch V8 while the GT500 came equipped with the 390 cubic-inch engine. In February of 1958, the GT500-KR became available and was considered the ultimate Shelby. Under the hood was a 428 cubic-inch Cobra-Jet V8 which produced 360 horsepower. The name 'KR' meaning 'King of the Road' was a quick marketing move by Carroll Shelby who had caught wind that Chevrolet was about to unleash a marketing campaign that highlighted the 1968 Corvette as the 'King of the Road.' After a quickly copyright search, they found that the 'KR' and 'King of the Road' had not been copyrighted. Stickers, photos, and decals were quickly made by Shelby and his crew and placed on the new GT500.

Located on the hood are function air-scoops which channel air to the engine. A 'Monte Carlo' bracing bar helps stiffen the car and chassis as the engine produces a large amount of torque. There were only 21 KR's produced with the white convertible top.

This 1968 Shelby GT500-KR Convertible finished in yellow, a 'Factory Special Paint', was offered for sale at the 2006 Worldwide Group Auction held on Hilton Head Island where it was expected to fetch between $250,000-$300,000. At the close of the auction, the vehicle had been sold for $258,500.By Daniel Vaughan | Nov 2006

At the 2006 Russo & Steele Auction in Monterey, Ca a 1968 Shelby GT500KR Convertible finished in yellow was offered for sale where it found a new home at the price of $275,000. It is an original car with 54,000 miles on the odometer. It is one of only 318 convertibles constructed and bears the Shelby serial number 4390. It is one of 21 built with special paint and the white convertible top.By Daniel Vaughan | Dec 2006